does TTL have the same stigma as auto mode on the camera?

Most slr enthusiasts would agree that manual mode (or at least Av or Tv) is the way to go, and that auto mode defeats the purpose of an slr.

When it comes to flash, is TTL frowned upon in the same way?

The reason I ask is because I have sb700's, but am considering two more yongnuo flashes for backlighting and fill. These are exclusively manual, so will they help me or hurt me? My flash experience has been exclusively TTL with the nikon CLS.

Does manual flash mode allow more control in the same way that manual camera mode does? Or is it more of a convenience thing?